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WHEN IT'S DREARY AND COLD
NEXT WINTER IN THE U.S. & CANADA . . .
. . . you can join us for another warm-weather
Tropical Hummingbird Expedition to
Costa Rica, Guatemala, or Belize
in January-February 2010

LOOKING OVER OVER-LOOKED CLOVER

Most days when we're not traveling to some distant locale we roll our bicycle up the gravel driveway at Hilton Pond Center, climb aboard our carbon fiber two-wheeler, and head out to explore the byways of York County. Depending on our schedule, we generally ride 15-30 miles, and sometimes more than that. We've become very familiar with local roadsides and take considerable pleasure from watching plants growing along the shoulder where they sprout, blossom, and eventually fade as seasons progress. The past few years we've become more attuned to a floral collection that is often ignored or even held in disdain. Yes, we've been looking over the often over-looked group known collectively as "clover."

All text & photos © Hilton Pond Center

Clover grows almost anywhere there's sufficient sun, so roadsides are indeed an ideal spot for them--as are suburban front lawns where homeowners sometimes curse clover's presence and persistence. Vascular Florida of the Carolinas (Radford, et al., 1968) lists 14 species of clover for those two states, few of which are native to North America. In fact, virtually all the clovers in the eastern U.S. came from Europe, North Africa, or western Asia, and all are obviously adapted to our soils and climate. Some folks might say they're TOO well-adapted and classify them as pernicious invasives, but because they often "rehabilitate" spoil places like roadside cuts and worn-out farms while growing leaf-to-leaf with natives, we're inclined to think they're not as undesirable as some foreign invaders.

All text & photos © Hilton Pond Center

All true clovers--of which there are about 300 species worldwide--are in the genus Trifolium, which means "three leaves." This name is a tad incorrect, however, because what appear to be leaves are actually leaflets (above). Such compound leaves are typical of members of the Pea Family (Fabaceae) in which clover is placed, along with relatives such as Mimosa, Eastern Redbud, Soybean, Honeylocust, vetches, wisterias, and--of course--all those peas and beans that fill our pantries. (Fabaceae is the third largest family of flowering plants, exceeded only by orchids and asters.) As shown above, clover leaflets are more or less symmetrical with mostly smooth (unserrated) edges, although those edges--and much of the clover plant itself--are typically adorned with fine, white hairs.

All text & photos © Hilton Pond Center

Perhaps the most obvious and among the most widely spread imported clovers is Red Clover, T. pratense; all three photos above are of this species and show a characteristic sharp white "V" on each pointed leaflet. Red Clover is one of our tallest clovers, reaching about 2.5 feet in height before falling over on itself. Its one-inch-diameter flower clusters vary from red to pink to purple and contrast nicely with roadside greenery as we cycle past. Red Clover flowers from April through September across the Carolina Piedmont; being a seed-bearing perennial it is capable of getting a roothold and colonizing an extensive area within just a few years. Red Clover, whose species epithet means "found in meadows," grows naturally in just such habitats throughout Europe; it is the national floral symbol of Denmark (although some Danes bestow that honor on the Marguerite Daisy.)

All text & photos © Hilton Pond Center

Especially familiar to many homeowners is White Clover, T. repens (above). It also bears a white letter on each leaflet, but the marks are more U-shaped and the leaflets more rounded than in Red Clover. White Clover's flowerhead is about a inch in diameter. This non-native perennial reproduces by seed and also by extending horizontal stems that allow it to weave between and flourish among grasses preferred by lawnsmen; in fact, its species epithet means "to creep." Oddly, White Clover used to be a main component of "grass seed mixes," primarily because it would sprout and grow where grasses would not and provide green soil cover.

All text & photos © Hilton Pond Center

The Carolinas are home to several yellow clovers--all imported--with one of the most common being Low Hop Clover, T. campestre (above). The species epithet means "of the fields," while the common name comes from the resemblance of the flowerhead to that of Hops. This low-growing plant has half-inch-diameter blossoms and oblong leaflets with sparsely toothed edges; the terminal leaflet has a short stalk. As an herbaceous annual or biennial it is not quite as prolific as Red or White clover.

All text & photos © Hilton Pond Center

One of our most delicate clovers is T. arvense, Rabbit Foot Clover (above), whose oblong, one-inch flowerheads are densely plumose. In the photo above shows only four actual flowers--the tiny white structures near the tip of the upper cluster. The rest of the flowerhead is comprised of feathery structures that apparently help deter seed predators and perhaps enhance seed dissemination. The fluffiness of these structures is reminiscent of a rabbit's foot, hence the common name; the species epithet means "from cultivated fields." Leaflets in this non-native clover are unmarked and quite narrow; at the base of each leaf is a pair of pinkish-red stipules.

All text & photos © Hilton Pond Center

One three-leaflet plant often mistaken for clover is oxalis or sorrel (above), which despite its tripartite foliage has very different five-petalled flowers and is in an entirely different family (Oxalidaceae). About eight species of native or naturalized Oxalis occur in the Carolinas, with several more ornamental species having been brought from the Old World. Oxalis is also known as "shamrock," although it should be noted the non-native Least Hop Clover, T. dubium, is actually the "lucky shamrock" chosen by St. Patrick to symbolize the Trinity.

Native or not, there's no question true clovers are an integral part of flora in North America, where they now serve as host plants for many species of native butterflies and moths. Clovers can be invasive, but as legumes whose root bacteria capture and fix nitrogen they are extremely important in replenishing soil ravaged by other nitrogen-depleting crops. Clover also provides highly nutritious graze for sheep and cattle, while clover seeds are taken in fall or winter by birds from sparrows to quail to Wild Turkeys. And clover's dried flowerheads can be ground into flour and its foliage makes a nutritious salad for wild foods enthusiasts (or bicyclists) who take the time to look over clover--a plant that's often overlooked.

All text & photos © Hilton Pond Center
Red Clover painting by Otto Wilhelm Thomé, Flora von Deutschland (1885)

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Be sure to scroll down for an account of all
birds banded or recaptured during the period,
plus other nature notes of interest.

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Laurie Yahr & Rich Kahl